Triterpenoids from the fruits of Phellodendron chinense Schneid. The stereostructure of niloticin.

Abstract

Three tirucallane-type triterpenoids, niloticin, phellochin and melianone, were isolated from the fruits of Phellodendron chinense SCHNEID. (Rutaceae). The stereostructure of niloticin was determined based on spectroscopic and X-ray crystal structure analyses. Furthermore, a derivative of niloticin and two derivatives of melianone were also found. A possible biogenetic pathway in P. chinense is proposed : niloticin → melianone → limonoids, on the basis of isolation of the compounds in different oxidation states.